(exclamation): Originating as a greeting by Chief Thunderthud (the only Indian ever to have a moustache) to the Peanut Gallery on the 50's television program "The Howdy Doody Show", the term was later adopted by surfers in the 60's.

Of course, surfers picked word up ― as Vermont Ferret wrote ― from Chief Thinderthud's greeting and his peanut gallery's response on the old time (1950s) children's TV show "Howdy Dowdy," an eponym for its cowboy manikin. Back then, on old corny Westerns, an Amerindian's greeting was stereotypically, "How!" to be rejoined with a "How!" So How morphed into Cow and an "abunga" was added for silly kid ― or those with Peter Pan syndrome ― fun.

Cowabunga is a slang term of surprise. It is incorrectly credited as becoming part of the lexicon when it appeared in the Ninja Turtle movies in the early 1990s. In fact this word dates back to 1964 when it was first heard in the movie "Pajama Party".